Early Platelet Counts Distinguish Viral and Bacterial Pulmonary Sepsis

Rationale: Respiratory viruses are commonly detected pathogens in pulmonary sepsis. Prior studies have demonstrated that patients with respiratory viral infections may have transient lymphocytopenia and thrombocytopenia. Leukocyte parameters including lymphocyte to monocyte ratio (LMR) and neutrophil to lymphocyte ratio (NLR) have been reported as screening tools for viral infections. Platelet counts and dynamics have been described as quantitative traits for ARDS risk and mortality. Therefore, we hypothesized that early hematologic parameters including lymphocyte count, monocyte count, platelet count, NLR, and LMR may distinguish viral from bacterial pulmonary sepsis. Methods: We enrolled 1,158 critically ill patients with pulmonary sepsis from 2009 to 2020 and measured lymphocyte count, monocyte count, platelet count, NLR, and LMR on ICU admission and at 24-hrs. Respiratory viruses were detected via PCR panel on nasopharyngeal swabs. Pulmonary sepsis was adjudicated by a physician panel. APACHE III scores were collected during the first 24-hrs. Shock was assessed by vasopressor use or mean arterial pressure